The Brazos Platform
After you have read this architecture overview, be sure you check out our AMD E-350 Zacate Fusion APU Performance results as well!!

Now that we have an idea of the inner workings of Bobcat, we can now explore the Brazos platform.  Brazos is comprised of at least two chips, and potentially three if combined with a “Vancouver” standalone graphics product.  Ontario and Zacate will make up the CPU/GPU/Northbridge, while the “Hudson” Fusion Controller Hub will handle all of the extended I/O functionality.

AMD Brazos and Zacate Architecture Preview - Bobcat Explored - Processors 13

We can see the low end positioning of the Brazos platform, as well as a new branding for the Vision program.  HD Internet may not be all that exciting, but it should be more than enough for its intended usage.

Zacate is the full 18 watt TDP part, and it will run at 1.6 GHz for the core CPU speed, and 500 MHz for the DX11 GPU portion.  That graphics portion is made up of 2 x 40 unit SIMDs, so it has a grand total of 80 stream processors.  If these follow the standard layout, each SIMD unit will also have 4 x texture units attached, so essentially double the texturing power as a AMD 880G integrated chipset, and four times the stream count.  It is quite an accomplishment to have this much stuff, running at those clockspeeds, yet still only have an 18 watt TDP.  Ontario has the same basic makeup, but is rated at 9 watts.

Each chip has a single, 64 bit DDR-3 1066 memory channel, so it will not have as much bandwidth as most desktop parts.  It also features 8 x PCI-E 2.0 lanes, four of which attach the APU to the FCH.  The other four can be used to communicate with a standalone graphics card.  These lanes can be run at half speed, basically giving PCI-E 1.0 performance per lane, for a nice power savings.

The Hudson FCH features SATA 6G functionality, as well as 14 USB 2.0 ports, and 2 USB 1.1 ports.  It also has the 4 PCI-E lanes to communicate with the APU, but it also has another 4 lanes to connect with peripheral chips such as Gig-E Ethernet controllers or WiFi controllers.

There are four distinct products being launched based on the Ontario and Zacate APUs:

AMD Brazos and Zacate Architecture Preview - Bobcat Explored - Processors 14

Edit:  Apparently I was mistaken, so apologies for getting it wrong.  The integrated graphics are in fact made up of 2 x 40 steam unit SIMDs, so 80 stream units in total.

All four of the APUs includes UVD3 and AMD-VTM.  I am still waiting on an answer, but it looks likely that these chips will support HD Audio bitstreaming through HDMI (courtesy of the UVD3 unit).  Once I get a final answer on that, I will update the article.  Edit: It appears as though the chip will in fact support HD audio bitstreaming.  According to AMD, the official specification sheet includes:  DTS-HD Master-Audio Bitstream Capable – Yes.

The one thing that will really pop out is the relative strength of the GPU in terms of stream units, but at the same time we are faced with single channel DDR-3 1066 bandwidth.  It has a theoretical bandwidth of approximately 5.5 GB/sec, which is a far cry from the 50 GB/sec that we see in low end standalone graphics parts.  Apparently due to the way the memory controller and caches are set up, it is less dependent on huge amounts of bandwidth.  It still makes a difference, but the DX11 GPU should be well fed enough to handle most modern games at lower levels of resolution and quality settings.

AMD Brazos and Zacate Architecture Preview - Bobcat Explored - Processors 15

In AMD’s analyst day yesterday, it was announced that the first APU products were being shipped from the packaging plant in Singapore to customers all around the world.  There are so far 100+ design wins based on the Brazos platform, and most of these products will be introduced under $500 US.

As AMD was showing these products, I was again struck by how incredibly tiny these chips are.  A full dual core CPU along with a pretty robust DX11 graphics chip only takes up around 75 mm squared of die space.  The 413 ball grid package was also very small, and the low pinout count also points to the comparative simplicity of this chip.  AMD is focused on stamping these out, and selling as many of them as possible.  So every penny was counted and saved when it comes to this very minimalist design.

AMD Brazos and Zacate Architecture Preview - Bobcat Explored - Processors 16

A few more specifics for the Brazos platform.  There is also a very good chance that this processor may not work at all in Windows XP with the graphics functionality.

The performance should not be considered minimalist though.  We expect some good things out of this little number, and considering how quickly they have ramped it to get it to market, and the amount of design wins that it has achieved so far, AMD has a lot to look forward to.  It may not be a high margin product, but it could become quite important to AMD’s bottom line in the years to come.

« PreviousNext »